Biochemical Investigations of Sugar-Modifying Enzymes

糖修饰酶的生化研究

• 批准号: 10548737
• 负责人: Hazel M. Holden
• 金额: $ 38.88万
• 依托单位: UNIVERSITY OF WISCONSIN-MADISON
• 依托单位国家: 美国
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-02-01 至 2025-01-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10548737
• 关键词: Acids; Acinetobacter baumannii; Anabolism; Antibiotics; Award; Bacteria; Bacteriophages; Biochemical; Campylobacter jejuni; Carbohydrates; Carbon; Categories; Cell surface; Complex; Data; Development; Drug Design; Enzymes; Glycoconjugates; Goals; Gram-Negative Bacteria; Immune response; Immune system; Invaded; Investigation; Kinetics; Knowledge; Link; Lipid A; Lipopolysaccharides; Membrane; Modification; Molecular; Molecular Weight; Monosaccharides; O Antigens; Oligosaccharides; Organism; Pathogenicity; Physiological; Play; Polysaccharides; Production; Research; Resistance; Role; Serum; Site-Directed Mutagenesis; Structure; Surface; Techniques; Variant; Virulence; World Health Organization; X-Ray Crystallography; antimicrobial drug; enzyme activity; macromolecule; phosphoramidate; sugar

PROJECT SUMMARY/ABSTRACT Bacteria produce an astonishingly diverse array of carbohydrate-based macromolecules that serve important physiological roles. The lipopolysaccharide or LPS, for example, is a complex glycoconjugate attached to the outer membranes of Gram-negative bacteria. Conceptually, the LPS can be thought of in terms of three regions: the lipid A component, the core oligosaccharide, and the O-antigen. It is the O-antigen that displays the most variation from species to species and that, in addition to the lipid A moiety, plays a role in virulence. Likewise, the capsular polysaccharides, which surround both pathogenic Gram-positive and Gram- negative bacteria, serve as the first lines of defense against the host immune system. These high molecular weight polysaccharides function by camouflaging cell surface components that would normally elicit the immune response. Often the sugars in the capsular polysaccharides are modified by the attachment of a variety of moieties including an O-methyl phosphoramidate group, which has been shown to be involved in host invasion and bacteriophage recognition. In addition, some capsular polysaccharides contain nonulosonic acids, nine-carbon based monosaccharides that have been implicated in virulence. The intellectual goals of this MIRA award are threefold: (1) to expand upon our current knowledge of the structures and activities of the enzymes involved in the biosynthesis of O-antigen sugars, (2) to provide a molecular framework for understanding the biosynthesis of the O-methyl phosphoramidate group in Campylobacter jejuni, and (3) to explore the structures and functions of the enzymes involved in the biosyntheses of nonulosonic acids from Acinetobacter baumannii, an organism that has been placed into the “Critical” category by the World Health Organization for the development of new antibiotics. Techniques to be utilized include X-ray crystallography, site-directed mutagenesis, and kinetic analyses. Importantly, preliminary data for many of the proposed investigations are already available. Our studies have and will continue to inform research into bacterial pathogenicity. Given that the LPS and capsular polysaccharides play critical roles in bacterial virulence, the enzymes to be investigated may ultimately serve as targets for antimicrobial drug design.

项目摘要/摘要 细菌会产生一个令人惊讶的多样化的基于碳氢化物的大分子 重要的身体角色。例如，脂多糖或LPS是一种复杂的糖缀合物 附着于革兰氏阴性细菌的外膜。从概念上讲，有限元可以在 三个区域的术语：脂质A组分，核心寡糖和O-抗原。它是O-抗原 这表现出从物种到物种的最大变化，除了脂质之外，还发挥了作用 在病毒中。 同样，囊状多糖围绕着致病性革兰氏阳性和革兰氏阴性 负细菌是针对宿主免疫系统的第一条防线。这些高分子 重量多糖通过伪装细胞表面成分的功能，通常会引起 免疫反应。通常，囊囊多糖中的糖通过a的附着来修饰 包括O-甲基磷酰胺组在内的各种部分，已证明参与 宿主入侵和噬菌体识别。此外，某些囊多糖含有非硫酸 酸，九个基于病毒中隐含的单糖。 该MIRA奖的智力目标是三重：（1）扩展我们当前对 与O-抗原糖生物合成有关的酶的结构和活性，（2）提供A 理解O-甲基磷酰胺基团的生物合成的分子框架 弯曲杆菌的空肠和（3）探索涉及的酶的结构和功能 来自鲍曼尼杆菌的非硫酸的生物合成，这是一种被放入的生物体 世界卫生组织开发新抗生素的“关键”类别。 要使用的技术包括X射线晶体学，定点诱变和动力学分析。 重要的是，许多拟议的调查的初步数据已经可用。 我们的研究已经并且将继续为细菌致病性研究提供信息。鉴于LP和 囊囊多糖在细菌病毒中起关键作用，要研究的酶可能 最终充当抗菌药物设计的靶标。